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HORIZONS Web-Interface
This tool provides a web-based
limited
interface to
JPL's HORIZONS system
which can be used to generate ephemerides for solar-system bodies. Full access to
HORIZONS
features is available via the primary
telnet interface
.
HORIZONS system news
shows recent changes and improvements. A
web-interface tutorial
is available to assist new users.
Current Settings
Ephemeris Type [
change
] :
OBSERVER
Target Body [
change
] :
Mars
[499]
Observer Location [
change
] :
Geocentric
[500]
Time Span [
change
] :
Start=
2013-05-20
, Stop=
2013-06-19
, Step=
1
d
Table Settings [
change
] :
defaults
Display/Output [
change
] :
default
(formatted HTML)
Table Settings
Select observer quantities from table below:
[
switch to manual-entry list-of-numbers form
]
Optionally preset observer quantities selection using one of the following:
1.
Astrometric RA & DEC
15.
Sun sub-longitude & sub-latitude
29.
Constellation ID
* 2.
Apparent RA & DEC
16.
Sub-Sun position angle & distance
30.
Delta-T (CT - UT)
3.
Rates; RA & DEC
17.
North Pole position angle & distance
* 31.
Observer ecliptic lon. & lat.
* 4.
Apparent AZ & EL
18.
Heliocentric ecliptic lon. & lat.
32.
North pole RA & DEC
5.
Rates; AZ & EL
19.
Heliocentric range & range-rate
33.
Galactic longitude & latitude
6.
Satellite X & Y, pos. angle
20.
Observer range & range-rate
34.
Local apparent SOLAR time
7.
Local apparent sidereal time
21.
One-way (down-leg) light-time
35.
Earth->obs. site light-time
8.
Airmass
22.
Speed wrt Sun & observer
> 36.
RA & DEC uncertainty
9.
Visual mag. & Surface Brght
23.
Sun-Observer-Target ELONG angle
> 37.
Plane-of-sky error ellipse
10.
Illuminated fraction
24.
Sun-Target-Observer PHASE angle
> 38.
POS uncertainty (RSS)
11.
Defect of illumination
25.
Target-Observer-IB / IB_Illum%
> 39.
Range & range-rate 3-sigmas
12.
Satellite anglular separ/vis.
26.
Observer-Primary-Target angle
> 40.
Doppler & delay 3-sigmas
13.
Target angular diameter
27.
Sun-Target pos. angle; radius & -vel.
41.
True anomaly angle
14.
Observer sub-lon & sub-lat
28.
Orbit plane angle
42.
Local apparent hour angle
Notes:
*
affected by optional atmospheric refraction setting (below)
>
statistical value that uses orbit covariance if available
Observer quantities are described in the
HORIZONS documentation
.
Optional observer-table settings:
date/time format :
Calendar Date/Time
Julian Day
Both
-- display date/time in year-month-day and/or Julian-day format
time digits :
minutes (HH:MM)
seconds (HH:MM:SS)
fractional seconds (HH:MM:SS.SSS)
-- controls output precision of time
angle format :
hours/degrees minutes seconds
decimal degrees
-- select RA/Dec output format
output units :
km & km/s
km & km/d
AU & AU/d
-- units for most output quantities
range units :
Astronomical Units
Kilometers
-- units for range-type quantities
refraction model :
airless model (no refraction)
standard atmosphere refraction model
-- select atmospheric refraction model
airmass limit :
-- suppress output when airmass is greater than this limit [1,38]
elevation cutoff :
(deg) -- suppress output when object elevation is less than this limit [-90,90]
solar elong. limits :
-
(deg) -- suppress output when solar elongation is outside this range
hour angle cutoff :
(h) -- suppress output when the local hour angle exceeds this value [0,12]
suppress range-rate :
-- suppress range-rate for range/range-rate output
skip daylight :
-- suppress output during daylight
extra precision :
-- output addition digits for RA/Dec quantities
RTS flag :
disable
true visual horizon
geometric horizon
radar horizon
-- output data only at target rise/transit/set (RTS)
reference system :
ICRF/J2000.0
FK4/B1950.0
-- reference frame for geometric and astrometric quantities
CSV format :
-- output data in Comma-Separated-Values (CSV) format
object page :
-- include object information/data page on output
2013-May-20 05:20 UT
(server date/time)
Site Manager:
Donald K. Yeomans
Webmaster
:
Alan B. Chamberlin
